Previously, all `m.room.*` events were wodged into `{{room_events}}` which
isn't great when you want to pull specific ones out. Batesian had a 1:1
mapping of `render_foo()` to a section `{{foo}}`, and having to constantly
add functions for new types is a PITA. Batesian now supports returning a
`dict` instead of a section `string` where the keys are the `{{foo}}` and
the value is what will be inserted. Also add conflicting section key checks
to avoid multiple definitions of the same `{{foo}}`. Define dicts for
event schemata and swagger HTTP APIs.
Using this new feature, split out the instant messaging stuff from the events
section, and replace `{{room_events}}` with a list of specific events e.g.
`{{m_room_member_event}}`.
Templates don't know at what level they will be inserted. Previously, we
hard-coded the title style which is not compatible with the build target
system. Define a set of styles which will be replaced by the gendoc script
when it encounters them:
'<' : Make this title a sub-heading
'/' : Make this title a heading at the same level
'>' : Make this title a super-heading
The build target system is now basically complete and functioning.
